This application relates to a guide which assists in a blind assembly of a fan drive gear to a bearing module, and in particular to the alignment of an oil tube between the two.
Gas turbine engines are known, and typically include a fan delivering air into a compressor. The air is compressed, and delivered into a combustion section where it is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors driving them to rotate.
Historically, at least two turbine rotors have been provided, and at least two compressor rotors have been provided. A first turbine rotor drives a higher pressure compressor rotor. A second turbine rotor has historically driven a lower pressure compressor rotor and the fan. These three components have all rotated at a common speed.
More recently, a gear reduction module has been positioned to drive the fan. This has allowed the fan to rotate at a slower speed than the low pressure compressor, which has many beneficial results.
However, assembling the gear reduction module into the gas turbine engine has raised many challenges.
In particular, the method of mounting the gear reduction module into the gas turbine engine includes bringing the gear reduction module in as an assembled unit, and mounting it within the gas turbine engine. The gear reduction module has been mounted through a flexible mount. A convolute is provided in an inner drive shaft as part of the flexible mount, and a flexure flange has been provided as part of the mounting of the gear reduction module into a bearing module.
A bearing module supports the drive shaft. An oil tube is mounted into one of the two modules (gear reduction and bearing), the two are assembled together, and the oil tube must be moved into the other.
However, the oil tube must be capable of pivoting movement within the mount orifices in both the gear reduction module and the bearing module. This is because the flexible mounting of the gear reduction module may result in large deflections of the two modules relative to each other. These deflections may occur during assembly of the modules as well as during normal engine operation.
Since the oil tube is free to pivot, it is difficult to predict its orientation when the gear reduction module is assembled to the bearing module. This problem is complicated, since the assembly is typically “blind.”